PK, if you like the sound of the RCA Black plate 12AU7...I do too...you should try a RCA Triple Mica 5814A...that's my favorite so far. In the 12AX7 spot, so far I've liked the GE Triple mica 5751s best...I've tried a pair of 1957 RCA Black plate 12AX7s and a pair of Raytheon 12AX7s there. I have one RCA Triple mica 5751 on the way and I'm looking for another one for about $50 to try in the ZP3. In the 12AU7 spot, I've tried more than a dozen tubes...I've lost count. Ain't this fun? Mark.

"The man that hath no music in himself, nor is not moved with the concord of sweet sounds, is fit for treasons, deceptions, and spoils;The motions of his spirit are dull as night and his affections dark as Hell. Let no such man be trusted." William Shakespeare

Peter, I definitely will...I'm hoping the RCA triple mica 5751s will beat out the GEs. I'm going to send an email to a favorite seller in the past to see if she has any. What are you running for a rectifier in your ZP3...I'm using a NOS RCA 5y3g and then a NOS RCA OA3 tops it off.

Let me know what you think of the RCA triple Mica 5814. Copy the link of what you bought, so I can have a look. Mark.

"The man that hath no music in himself, nor is not moved with the concord of sweet sounds, is fit for treasons, deceptions, and spoils;The motions of his spirit are dull as night and his affections dark as Hell. Let no such man be trusted." William Shakespeare

Peter, the NOS OA3's are dirt cheap, buy several for back up and other Amps in the future...I use them in my newly acquired SE84ZSM Monoblocks and my Torii MK IV. I've never tried others in this position.

Get rid of that Chinese tube...yes, the RCA 5Y3G works there and seems to be the preferred tube for that position in the opinion of many here. It's the only one I've used besides the stock one briefly. But if you prefer, you can use a NOS RCA 5U4G...I use these in the Monos...they're nice.

I just went and looked at the owners manual...link below. And the picture has a 5Y3GT in that spot and on page 4 they talk about the tubes. It would appear that the ZP3 was originally voiced with the 5Y3 type rectifier but I know the 5U4 types work too. Mark.

"The man that hath no music in himself, nor is not moved with the concord of sweet sounds, is fit for treasons, deceptions, and spoils;The motions of his spirit are dull as night and his affections dark as Hell. Let no such man be trusted." William Shakespeare

PK, if you see a good deal on a NOS OB3, those are worth a listen. I used to prefer the OA3 but have been running OB3 for some time now. These seem to work differently with different rectifiers and input tubes and offer usefulness as fine-tuning tubes.

Until recently the GEs were my favorite...the RCA 5751s were then a little better, maybe a bit warmer but I put in the Sylvanias yesterday and they are by far my favorites now. I'll have to think for a couple days before I can put the sound into words...I'm not too good with the "Audio Lingo". All I know is I love them. These are the ones with Blk Plates and steel pins that were made for the military or sold under the Gold Brand....NOT the Grey plate with gold pins, Gold Brand 5751 version that also is very popular and expensive. Reading the descriptions, I thought I'd like the cheaper Black Plate/steel pin version....appears I was right. I paid about $110 plus shipping for my pair and another in the mail. I plan on picking up another set if I see a good testing pair for less than $100. Try them...you'll like them! Mark.

PS...I should say all of the tubes I tried sounded good in the ZP3. You can't go wrong with any of the 12AX7 types I've used. The RCA or Raytheon Black plate 12AX7 and the RCA Black plate 12AU7 would be an affordable and great sounding option for those on a budget.

"The man that hath no music in himself, nor is not moved with the concord of sweet sounds, is fit for treasons, deceptions, and spoils;The motions of his spirit are dull as night and his affections dark as Hell. Let no such man be trusted." William Shakespeare

That's not good. Luckily there are a lot of good testing ones on ebay. Why don't you try a GE triple Mica Black Plate 5814A and let me know how they sound. I've been tempted to try one, they're a bit cheaper but should be great...or buy both a GE and a RCA. Mark.

"The man that hath no music in himself, nor is not moved with the concord of sweet sounds, is fit for treasons, deceptions, and spoils;The motions of his spirit are dull as night and his affections dark as Hell. Let no such man be trusted." William Shakespeare

Yes Peter, I have found the 12AU7 spot to have a sometimes dramatic effect on the sound of the ZP3. Plus, since you only need one tube, it was easy and relatively inexpensive to try a lot of them...Mullard, Amperex, RCA, Mazda, GE...are manufactures I've tried with multiple variants. Only recently have I started experimenting with the 12AX7 spot. These tubes are more expensive.

I always thought the 5751 were quieter with less microphony because of the reduced gain factor of 70 and thick triple mica construction with added support rods. I just read the below...

"The gain factor of a tube simply measures how much it amplifies the input signal. For example, the common 12AX7 tube has a gain factor of 100, while a 5751 tube (which is often used in place of a 12AX7) has a gain factor of 70. This means that if you plug a 5751 into a socket that expects a 12AX7, the pre-amp will have about 30% less gain. Not only will this make the amp quieter, but it can also alter the sound by making the power section work harder when you turn it up. Many guitar amp users (particularly harmonica players) like to reduce the gain to get a different sound or calm the amp down to prevent feedback."

What Amp are you using and do you use a preamp? Also you need to use a shielded cable between the Amp/Preamp and ZP3...in every other position I use the Decware DSR 1 meter interconnects. In my Torii I once used 5Y3GT rectifiers when I had trouble with intermittent distortion. Once I changed to a 5U4 type, almost all distortion was gone. With my revealing system, I've found I now hear the faults of the original recordings more often.

I've never tried Telfunkens anywhere. When I've read the descriptions, I've been led to believe they would be Brighter/Hotter than the Black Plates I like. Anyway, let us know what you do. Mark.

"The man that hath no music in himself, nor is not moved with the concord of sweet sounds, is fit for treasons, deceptions, and spoils;The motions of his spirit are dull as night and his affections dark as Hell. Let no such man be trusted." William Shakespeare

Peter, Have you read "Joe's Tube Lore". I'll give the link below. As you read, remember that he was probably using a different pre amp and gear than you. Also his tastes may be different than your's. So don't exclude a tube solely because he didn't like or list it. With those caveats, I've found his post from the late 90's to be very helpful. Unfortunately, I also think his views have been partly responsible for many of his favored tubes dramatically increasing in cost since he revealed his lists.

I went back and read what he said about Telfunken and Mullard 12AU7 type tubes...I copied it below. This is why I haven't tried one. I have tried a Mullard CV 4003 from Upscale Audio...I liked it, just not better than my favorite Black Plate types made by RCA. It's worth reading his lengthy thread. Mark.

"Now shifting back to the present, the only other comments I might add relate to the obvious "what about the Mullard rib plates & legendary Telefunkens?" question. Well frankly there wasn't much to say. IMHO these are two of the most overrated brands in the NOS universe. generally speaking all the Telefunken 12A family tubes I've heard ('X7s, 'T7s, 'U7s) are a bit bright, thin and airy sounding. I've talked to Charlie Kittleson at Vacuum Tube Valley about this and he basically agreed, observing that these guys more or less built their reputation on their use by the old gear crowd. Why? Well his comment was that the caps, resistors & transformers in old gear were dark sounding sludge and the Teles offered a useful brightening of the sound to a more natural balance. The issue, of course, is that when you put them in a contemporary design with much wider bandwidth and a more neutral '90s kind of balance things can go over the top.

Now before any Tele lovers who find them ideal in their new gear freak out and tell me how wonderful they sound - I believe it. There is a system out there somewhere that's the ideal match for any tube. This is just a comment on a general tendency. Now Mullards are another matter. I have found a few that sound quite nice and they generally are warmer than Teles, but in my rig they never quite make it to the top of the heap."

"The man that hath no music in himself, nor is not moved with the concord of sweet sounds, is fit for treasons, deceptions, and spoils;The motions of his spirit are dull as night and his affections dark as Hell. Let no such man be trusted." William Shakespeare

"5751: This version was usually the one made for the US military. These have a lower gain than the 12AX7, but are otherwise totally compatible. Great hi-fi tubes, as the lower gain reduces noise and microphonics. These are all ruggedized and most can withstand a drop on the floor. The internal triode elements are matched as well. The early versions are more sought after as they usually have extra support rods and an extra mica spacer on top of the plate structure ("Triple Mica"), as well as blackplates, all said to contribute to low microphonics. Don't overlook the greyplate versions, they are also excellent tubes, and many of these have the triple mica as well. The GE non-military version is usually the "five star" series, intended for broadcast use. The RCA broadcast type is the "Command" series. Both the RCA and GE broadcast types are scarce, as are any of the triple mica types."

"...the Sylvania 5751 variants are very balanced and pleasant to listen to for hours. The GE blackplate 5751 triple mica is also in great demand as a very musical vintage tube. The RCA 5751 is more like the Mullard, with a rich warmth and wide bandwidth. Currently, the USA made tubes are a nice surprise with their low prices as compared to the European types."

"The man that hath no music in himself, nor is not moved with the concord of sweet sounds, is fit for treasons, deceptions, and spoils;The motions of his spirit are dull as night and his affections dark as Hell. Let no such man be trusted." William Shakespeare

Peter, your gear is very different than mine so what you are hearing may be quite different but I think generalizations should still apply. I like Black Plate 12AU7 and 12AX7 tubes...to me they seem warmer and richer in character... smooth and detailed. I tallied up what I've spent on the 5157's I've bought recently...I was a little shocked...hehe. Except for another pair of the Sylvania 5751s at a great price, I think I'm done buying tubes to roll in the ZP3. I do plan on trying a mid fifties RCA 5U4G in place of the RCA 5Y3G in there currently. Also I'll try a 1960 Tung Sol OA3 instead of a 50's RCA OA3 currently in place.

In regards to the Telfunken ribbed plate 12AX7...this is what Joe had to say...again his descriptions of the teles has discouraged me from trying them.

"Telefunken 12AX7 ribbed plates - a typical soft, unfocused 12AX7 sound with big, soft, images allied with a bright bass shy character. I was shocked when I heard these guys first hand, but the more I talked to people who knew these tubes the better I understood them. I generally associate NOS tubes with a warmer, more harmonically complex & rich sound than current production, but light and airy is the order of the day here - to the pint of brightness. The secret is that these guys are a favorite for use in a lot of old classic gear from the '50s & '60s where the transformers, wire and caps used were thick, dull sounding sonic sludge. The bright balance of this tube is great complement for this kind of gear, but drop it into current broad bandwidth tube gear (like the Thor) and you might just get sonic hell - all for just $50 to $65 a tube!"

Your original post last night has me reading through the ZP3 thread. has anyone else reading this used 5751's in the ZP3? If so I'd like your impressions. Next I'll concentrate a little on input tubes...so far I've tried the stock Russian tubes, Amperex 7308's and Amperex Bugle Boy 6DJ8's...all sound different but good. PK any favorite 6922 tube types? Keep on Rolling fellas, Mark.

"The man that hath no music in himself, nor is not moved with the concord of sweet sounds, is fit for treasons, deceptions, and spoils;The motions of his spirit are dull as night and his affections dark as Hell. Let no such man be trusted." William Shakespeare

Peter, you don't have to try a GE Blk Pl Triple Mica 5814A...I just bought two for $35 including S&H. I suspect they'll be similar to the RCAs, which would be good because they are much cheaper. I'll let you know how they sound. Mark.

"The man that hath no music in himself, nor is not moved with the concord of sweet sounds, is fit for treasons, deceptions, and spoils;The motions of his spirit are dull as night and his affections dark as Hell. Let no such man be trusted." William Shakespeare

I learned the following from Steve Deckart of Decware about the tubes for the ZP3,

The first tube slot at the front in the most important tube, it is the input tube running in stereo from one tube (I am using either a GE Triple Mica Blackplate 5751 or a Tele 12ax7 ribbed plate).

The second slot for the 12ax7 tube is the output tube. This tube does NOT need to match the input tube, it may be an entirely different brand (this will drive me a little crazy, because I like to tube roll, and I have a bunch of single 12ax7 tubes sitting around).

I have found that each old stock mystery 12ax7 tube from my tube stash has a different sound. I am in the process of picking the one with the lowest distortion while providing great sound.

The third slot for a 12au7 is a tube buffer and must be a 12au7 or equivalent like a 5814a . I am using a RCA Triple Mica Blackplate 5814a and a NOS Mullard Blackburn Factory branded Valvo in this slot.

New old stock, original and white Box. Grey plates, very similar to the very rare Mazda silver plate tubes. These are also hard to find in the USA. Excellent, 1960s vintage long lived 12AU7 types with the distinct European vintage flavor that a modern tube just cannot capture! These have the sweetness and dynamic punch typical of Mazda

New Old Stock in whiteboxes. These are the genuine 1950s vintage Raytheon shiny blackplates. For a short time we have a very limited special LOW PRICE on these rare tubes made for organs, some OEM repair stock with no labels. Nothing like these are likely to ever be made again, and these have the added advantage of being factory screened for use in organ audio circuits. These beauties rival the vintage European 12AX7s, and are the best bang for the buck going in a vintage USA made.

12ax7 (middle tube or second from front, for RIAA curve): NOS Telefunken from my stash

New old stock, original and white Box. Grey plates, very similar to the very rare Mazda silver plate tubes. These are also hard to find in the USA. Excellent, 1960s vintage long lived 12AU7 types with the distinct European vintage flavor that a modern tube just cannot capture! These have the sweetness and dynamic punch typical of Mazda

I am running nos mullard 12ax7 cv4004's in the first and second slot with another nos mullard 12au7 in the last spot. They are tremendous but have also skyrocketed in price in the 2 yrs I've owned them. I also enjoyed NOS Mazda's and a Radiotechnique in the 12au7 role but didn't give em enough time to break in.

In the past I've used a Mullard in all three spots, all pulled from my '59 EICO HF81. These tubes have lots of use and are probably not at their best. The sound was far too thick and rich with these in place, great for some ops but in general not the best fit. I've been using Raytheons in all positions with great success. Steve sent one with the amp and I bought two others from tgarden.

Well I won the Mullard, so looking forward to it`s arrival. The other day I bought another 12ax7 on e-bay, it`s all marked up in military print, like a Brimar I have. The seller says origin unknown, maybe Chinese, excellent sonics. He`s sold 900 nearly and has loads more. If it`s any good I`ll get some more. Dirt cheap.

Brent Jessee is a pleasure to deal with, he allowed me to try various tubes until I found the best, Hammond and the Mazda are amazing tubes

Brent provides a 30 day return privileged on Tubes!!!!!!!

Also I upgraded to a NOS RCA 5U4G Coke Bottle (Brent Jessee) and a Green Label on Base Coke Bottle Sylvania NOS OA3 (upgrade for OA3 from Decware).

Mazda 12au7 info;

New old stock, original and white Box. Grey plates, very similar to the very rare Mazda silver plate tubes. These are also hard to find in the USA. Excellent, 1960s vintage long lived 12AU7 types with the distinct European vintage flavor that a modern tube just cannot capture! These have the sweetness and dynamic punch typical of Mazda.

A lot of good tube options here, so thank you all. My ZP3 will be arriving in 2-3 weeks. I've ordered from B-Jessee nos 12AU7 cleartop rca rebranded for Conn organ & nos 5Y3GT 50's rca. Gonna let ZP3 cook for 2 or 3 weeks before I roll in nos tubes. I also have some 0A3 RCA 1951' to try as well as some rectifiers bought for my superzen that I will experiment with as well. Will let everyone know my findings/ liking's once this long process is finished....ahh now I need some patience!

Hi all - I have had my ZP3 for a couple of months now and tube rolling. Lots of good comments here. What I am liking in the first 12AX7 slot (closest to the front) is GE triple mica black plate and Raytheon triple mica black plate, and Mazda NOS 12AX7S (these are expensive, but VERY VERY nice sound). I did not like the TLFKN 12AX7 or GE JAN 5751 dual mica or CBS 12AD7 in this spot. EI 7025 also scored very high for me. I want to get more hours on my favorites and then review them all again. I am thinking I will put fav #2 in the 2nd 12AX7 slot and then tube roll the 12AU7 slot.

Lots of fun. And of course the sound is incredible.

I have an old Oracle Alexandria TT with Clearaudio Aurum Beta, ZTPRE (pre-prod version) and Zen 84CKC amp thru a pair of Zen Open Baffles. I will be upgrading to a VPI Prime with Ortofon 2M Black . That should make a big difference.

I substituted a NOS Mazda in my second 12ax7 slot and tried it for a couple weeks. A couple of my hard core blues buddies came over the other night and we spent a few hrs listening to Junior Kimbrough and Lightning Hopkins. They thought it sounded it great but i wasn't too happy except for the Whistlepig rye they brought. I put my NOS Mullard back in and boy am I happy. IMO the ZP3 and tube burn in make a huge sonic difference, much more evident than in my CSP2+ or Torii III. I find a matched pair in the 12ax7 slots really makes a difference. It takes time but wow when you find some tube synergy it is breathtaking.

I've tried my normal lot of old 12AX7 tubes and settled on some Telefunken SP tubes that seem to add an enjoyable delicacy to the higher frequencies. Still using the 12AU7 and 274B Steve shipped but I found an old JAN 0A3 that is prettier than the other.

Between these, the stock tubes and the assorted other OB's and rectifiers I have, I'll be set for awhile. Only have about 25hrs on the zp3 at this point so it's far from seasoned, but it'll still be fun to do some rolling. I'm off for 6 days starting Thursday. Guaranteed I'll be logging some major hours on the stereo then. Can't wait.

Nice tubes. Those Raytheon black plates were the first NOS 12AX7s I had in my ZP3...they sound very good as do anything RCA Black Plate. I use a pair of the raytheons in both my Jolida 100 CDPs. I've never tried a 5U4G in the ZP3. But have them in both Amps. Mark.

"The man that hath no music in himself, nor is not moved with the concord of sweet sounds, is fit for treasons, deceptions, and spoils;The motions of his spirit are dull as night and his affections dark as Hell. Let no such man be trusted." William Shakespeare

Greg, I just read this thread again and I've outlined my experience in the past. I roll the 12AX7 spot every 1 or 2 months but the 12AU7 spot hasn't changed since at least June. So currently I'm still using the RCA Triple Mica Black plate 5814 and have 4 more in the mail bought cheaply on ebay. In the 12AX7 spot I've been running for the past month a pair of Military Sylvania triple mica, black plate, steel pinned, 5751s. This is my favorite combo so far. But the gain with the 5751 is 70% of the 12AX7s so this may be a problem with your cartridge since it's a MC used without a SUT. Mark.

PS...I think for a change, I'll leave the 12AX7 spots alone and roll the 12AU7. After reading what others liked, I'm going to try a Mazda 12AU7 and a Mullard CV4003 in that position. I've got a couple of each somewhere.

I can't remember who I bought them from but they were originally from Upscale Audio...the links below describe them at Kevin's site...

"The man that hath no music in himself, nor is not moved with the concord of sweet sounds, is fit for treasons, deceptions, and spoils;The motions of his spirit are dull as night and his affections dark as Hell. Let no such man be trusted." William Shakespeare

You bring up a great point Mark about the 5751 potentially under powering my MC. I wouldn't have thought that so thanks. I guess I'd want to try as cheap a one as I can find and see how it performs before spending on the spendy ones you've linked to. $95. Whew!

I'll tell you what though, even if I didn't buy another tube, I could live with the sound I'm getting with the stock tung-sols and the Philips 5R4GYS. Beautiful. Makes me think I should snag a Brimar 5R4GYS as Lord Soth feels its even better yet.

Greg, you shouldn't feel the need to try the 5751's, they are all expensive especially the triple micas...but if you can't resist, the GE Black Plate triple mica 5751's are cheaper than RCA and Sylvania entries. You also can save at least half of what Brent Jesse charges by using ebay. I really think your choice of the raytheon and RCA black plates is excellent and if you were to stop there you wouldn't be missing much. Mark.

"The man that hath no music in himself, nor is not moved with the concord of sweet sounds, is fit for treasons, deceptions, and spoils;The motions of his spirit are dull as night and his affections dark as Hell. Let no such man be trusted." William Shakespeare

Theres no need to go for 12ax7 pairs really as they do different jobs. The more singles you pick up can be swapped around. I look for different getters as well. The ones in my ZP3 have a disc with a punched indentation. They are a pair though as I liked the first one, so because they were cheap got another. Syd

Syd, even though I know that, due to someone sharing earlier in this thread, I still can't bring myself to do it. I still put pairs in the 12AX7 spots. The combinations would be near infinite otherwise...hehe. Mark.

"The man that hath no music in himself, nor is not moved with the concord of sweet sounds, is fit for treasons, deceptions, and spoils;The motions of his spirit are dull as night and his affections dark as Hell. Let no such man be trusted." William Shakespeare

Sylvania 7025 / 12AX7 60'sthe pair tungsols that came with it 12ax7RCA 50's 5Y3GTValve Art 274B that came with itPhilips 5R4GYSSvetlana =C= 5U4G/5C3S bottle shape 70's the 12au7 that came with it (mfg ?)RCA 50's black plate 12au7 Sylvania 03ASylvania 0CAA few other

Ok, time to resurrect this thread. I've been rolling some different tubes through the 12AX7 spots of the ZP3. My current lineup below...

12AU7 spot...a RCA Triple Mica Black Plate 5814

Middle 12AX7...I acquired a pair of Sylvania Triple Mica Gray Plate 5751s that I have really been enjoying recently in both 12AX7 spots until tonight.

Front 12AX7...tonight I put in a 60's Mullard I63 12AX7A that I'm really liking...vocals incredible...Ella was amazing with this combo.

For completeness...I use a coke bottle 50's RCA OA3 and 5Y3G. I don't roll these but I do have a 1960 pair of Tung Sol OA3s I could try and several different 5U4Gs I could try. But don't feel the need.

Now the real reason for my post. Looking at the tubes Steve sells...he has 12AT7s listed as a higher gain Sub for the 12AU7. Has anyone tried one in the ZP3? I've seen them on ebay and they are always less expensive than the same brand/year of the 12AU7. Mark.

"The man that hath no music in himself, nor is not moved with the concord of sweet sounds, is fit for treasons, deceptions, and spoils;The motions of his spirit are dull as night and his affections dark as Hell. Let no such man be trusted." William Shakespeare

Ok Syd, I guess I won't try it. Besides, I already have a lot of the 12AU7s, including Mullards, Amperex, RCAs, Mazda, Phillips miniwatts, etc as well as several variants. I guess I'll concentrate on trying different 12AX7 types. I'm thinking an Amperex 60's white label 12AX7...have you tried this one? I really like their 6DJ8, 6299 and 7308s...I use them in two amps and my pre amp. Mark.

"The man that hath no music in himself, nor is not moved with the concord of sweet sounds, is fit for treasons, deceptions, and spoils;The motions of his spirit are dull as night and his affections dark as Hell. Let no such man be trusted." William Shakespeare

I used to say I disliked all the hardware aspect of Audio...trying and reading about gear, speaker cables, etc....preferring to just sit back and listen to the music without considering all the details needed to get there. This is still largely true. My recent interconnect and speaker cable experimentation is like pulling teeth...not something I find enjoyable. And as a result it's taking me forever to come to conclusions.

But I have come to the conclusion that I do enjoy tube rolling. I enjoy reading about the history of tubes and getting into the art of reading date codes and examining the internal structure of tubes to reveal who actually made a specific tube...and finally I really like the result of changing a tube.

I mainly have been tube rolling in my ZP3 but have recently also been trying more input tubes in the CSP3 and Zen Signature Monoblocks. The newest ebay purchase last night was an Amperex Bugle Boy 1959 I61 12AX7...as well as another Amperex BB 6DJ8, I already have one pair. Mark.

"The man that hath no music in himself, nor is not moved with the concord of sweet sounds, is fit for treasons, deceptions, and spoils;The motions of his spirit are dull as night and his affections dark as Hell. Let no such man be trusted." William Shakespeare